1. Field of the Invention
The present invention relates to a water wheel impeller blade type electric power generating apparatus using a water stream, a seawater current or the like in, for example, a river or the sea to generate hydroelectric power.
2. Field of the Related Art
As the water wheel impeller blade type electric power generating apparatus, the applicant of the present application has proposed one having a structure as shown in FIG. 17 and FIG. 18 in Patent Document 1. This structure includes a rotating shaft for transmitting motive power to the power generator, a rotor fixed to this rotating shaft, and impeller blades which are provided on the outer periphery of this rotor for rotating said rotor by receiving a flow of fluid. In addition, under said rotor, a fluid passage frame body is provided such that a fluid passage is formed, and said impeller blades have a fluid receiving part and a stopper part shorter than this fluid receiving part, being formed in the shape of a letter L, and are rotatably disposed on said rotor such that, when said fluid receiving part is exposed to the fluid pressure in said fluid passage, said stopper part can maintain erection of said fluid receiving part.
For the outer periphery of said rotor, the blade passage frame body is provided such that it surrounds the rotor without hindering the rotation of said impeller blade. Said fluid receiving part is provided with a weight on the surface opposite to the fluid receiving one, or said fluid receiving part is comprised of a fluid receiving portion as the base, and a weight fixed to the distal end thereof. The outer periphery of said rotor is contoured such that, outside the area where the distal end of the fluid receiving part is butted against the outer periphery is formed in the shape of a circular arc with a thickness larger than that of the area where the rotating support shaft for said impeller blade is provided, and further, in the surface of the rotor, a concave is formed in the shape of a circular arc on the side of the stopper part.
Patent Document 1: Japanese Patent Application No. 2009-104591 (Japanese Patent Laid-Open Publication No. 2010-151117)
The water wheel impeller blade type electric power generating apparatus as disclosed in Patent Document 1, which having a structure as shown in FIG. 17 and FIG. 18, features that, because the fluid flows under the water wheel (including the rotor and the impeller blades), the mud, sand, dirt, and the like in the river will not be collected into the water wheel. In addition, because the impeller blade is thrust down on the backward motion side, the resistance is reduced during the backward motion. Further, the impeller blade mounting surface of the rotor is contoured in the shape of a circular arc in order to reduce the fluid resistance, and further a concave in the shape of a circular arc is formed on the stopper part side in order to facilitate the erection of the impeller blade. Furthermore, the fluid receiving part of the impeller blade is provided with a weight on the surface opposite to the fluid receiving one, or a weight is fixed at the distal end of the fluid receiving portion. Thus, the rotor and the impeller blade have a complicated structure, increasing the manufacturing cost.
It is an object of the present invention to provide a water wheel impeller blade type electric power generating apparatus with which, on the forward motion side, the hydraulic pressure applied to the impeller blade is reduced; the mud, sand, dirt, and the like will not be collected into the water wheel; the manufacturing cost for the apparatus can be reduced; and further by utilizing the buoyancy force of the fluid, the load imposed on the bearings which pivotally support the rotor is reduced or practically eliminated, whereby heat generation of and damage to the bearings are prevented, and the fluid energy loss is reduced to allow improving the durability and the power generation efficiency.